KIF5 (also known as kinesin-1) family members, consisting of KIF5A, KIF5B, and KIF5C, are microtubule-dependent molecular motors that are important for neuronal function. Among the KIF5s, KIF5A is neuron specific and highly expressed in the central nervous system. However, the specific roles of KIF5A remain unknown. Here, we established conditional Kif5a-knockout mice in which KIF5A protein expression was postnatally suppressed in neurons. Epileptic phenotypes were observed by electroencephalogram abnormalities in knockout mice because of impaired GABA_A receptor (GABA_AR)-mediated synaptic transmission. We also identified reduced cell surface expression of GABA_AR in knockout neurons. Importantly, we identified that KIF5A specifically interacted with GABA_AR-associated protein (GABARAP) that is known to be involved in GABA_AR trafficking. KIF5A regulated neuronal surface expression of GABA_ARs via an interaction with GABARAP. These results provide an insight into the molecular mechanisms of KIF5A, which regulate inhibitory neural transmission.